In connection with manipulating apparatus and robots, the sensor problem presents itself again and again, since sensors are the necessary prerequisite for locating, recognizing, or grasping objects by means of a robot or a manipulating arm. Normally a large multitude of different sensors is employed; thus, for example, ultrasonic sensors, electronic cameras, laser or radar sensors find application. Likewise, light barriers are used for locating objects and are especially effective when several light barriers work together in a light-barrier matrix. However, other sensors can also be combined in a matrix.
The position of an object within a light-barrier matrix can be determined relatively easily by checking which of the individual light barriers, or rather, light beams are interrupted by the object. Here, however, faulty readings can result when one or several of the light barriers are interrupted not by the object to be located, but rather by, for example, dirt. In a light barrier the dirt can cling, for example, to the light receptor or the light source. In both cases the light barrier is constantly interrupted.
The operational range of the sensor matrix of a milking robot is usually in the narrow sense the area surrounding the teats of a cow and in the broad sense a milking box in which a cow is to be milked. The sensor matrix is located in most cases on the end of a robot or manipulator arm in the vicinity of a holding device for teat cups. Thus, as a rule the sensor matrix is moved along with the robot or manipulator arm.
The problem forming the basis of the invention is to specify a process by which faulty readings due to a completely or partially soiled sensor matrix are avoided.